A ball is dropped from the top of a building that is 250 feet tall. The height h of the ball in feet after t seconds is modeled by the function h = -16t2 +250. How long will it take for the ball to reach the ground? Round your answer to the nearest hundredth if necessary.

Question

anonymous · Answer

set the equation equal to 0 and solve

anonymous · Answer

can you set it up for me? I'm confused

math&ing001 · Answer

The ball will hit the ground when h=0.

jdoe0001 · Answer

have you done  quadratics yet?

anonymous · Answer

nooo

jdoe0001 · Answer

hmmm well, you may want to cover quadratics first, since that's what you have there

campbell_st · Answer

well you don't need quadratics... since it hite the ground when h(t) = 0

so you have 

$$0 = -16t^2 + 250$$

the equation can be rewritten as

$$16t^2 = 250$$

now solve for t

campbell_st · Answer

only use the positive value as time can't be negative.

anonymous · Answer

ooh okay, do i divide both sides by 16 then take the square root?

anonymous · Answer

bingo

anonymous · Answer

awesome!

campbell_st · Answer

thats correct...

anonymous · Answer

thank you so much!